In general, a vacuum circuit-breaker for a large current is constructed so that a pair of separable electrodes are disposed in a vacuum vessel, and rods connected to the rear surfaces of these electrodes extend to the outside of the vacuum vessel. Each pair of the above electrodes is composed of an are electrode portion on the front surface side and a coil electrode portion on the rear surface side which are opposed to each other. A current flows from one rod to the other rod by way of the coil electrode portion and the arc electrode portion of one electrode, and the arc electrode portion and the coil electrode portion of the other electrode. For breaking the current, any one of the rods is moved by an operating device so as to separate the arc electrode portion of one electrode from the arc electrode portion of the other electrode. At this Lime, an arc is generated between both the arc electrode portions. This arc is dispersed in the filiform manner by a magnetic field generated in the axial direction, that is, in parallel to the arc by the current flowing in the above coil electrode, to be extinguished.
Incidentally, for example, as disclosed in Japanese Patent Laid-open No. SHO 62-103928 (U.S. Pat. No. 4,704,506), the prior art electrode of this type which is composed of the arc electrode portion and the coil electrode portion is constructed as follows. The portion which contacts an arc in the arc electrode portion is formed by a machining step such as cutting a metal member excellent in withstand voltage performance and current-breaking performance, for example, one obtained by infiltration of a high conductive metal such as copper in voids of a high melting point metal such as chromium. Further, the coil electrode portion is formed by a machining step such as cutting inclined or circumferential slits on the side surface of a cylindrical member made from a high conductive metal such as copper, wherein the above slitted portion is adapted to allow a current to flow therethrough in the circumferential direction. The arc electrode portion, coil electrode portion, and the rod are electrically and mechanically connected to each other by hard brazing such as by silver brazing.